The Des Moines Register and Tribune Co. said yesterday it will negotiate with Rosslyn-based Gannett Co. Inc. on the sale of The Register's 14 percent stake in Cowles Media Co., publisher of the Minneapolis Star and Tribune.

Register Chairman David Kruidenier, who also is chairman of Cowles Media, said yesterday he believes an agreement with Gannett will be completed and approved when The Register board meets on April 30. Gannett, publisher of USA Today and the nation's largest newspaper chain, was the winning bidder for The Register's newspaper operations, with a $200 million offer.

The Washington Post Co. announced earlier this month that it has agreed to acquire 17 percent of Cowles Media from a dissident Cowles stockholder. Wall Street experts said yesterday that as the two largest minority stockholders, The Post Co. and Gannett could end up in a battle for control of Cowles Media.

Kruidenier said yesterday Cowles Media is not for sale. He said the company would be under less pressure to sell with two companies as large minority shareholders.

While about half of Cowles Media stock is held in a trust and the company repeatedly has said it is not for sale, speculation that it might be sold has increased recently. The Cowles family decided in December to sell The Register Co. after making similar statements that it was not for sale.

In addition to the Minneapolis Star and Tribune newspaper, Cowles Media owns the Rapid City Journal in South Dakota, the Great Falls Tribune in Montana, the South Idaho Press in Burley, a group of suburban newspapers in Denver, and a commercial and directory printing business.